I think the way to interpret that comment is that if the killer had simply gotten into a fist fight after class, like many of us here (including me) did to resolve disputes, things probably would've gone differently.

I was viciously bullied from 3rd grade through 6th and eventually stopped it through physical violence. The guy who bullied me (we exchanged black eyes on multiple occasions) ended up being one of my best childhood friends and I attended his father's funeral last year after he was killed in a tragic accident. Fighting amongst boys is normal.